This project will interview adolescents with CF and their parents to discover and document barriers to and facilitators of self-management, use this knowledge to complete development of an innovative intervention to promote self-management, and then conduct a formative evaluation of the intervention. The Peer Group Intervention will incorporate the crucial element of personal meaning, which we theorize will lead to more robust effects than prior interventions based solely on constructs from social cognitive theory. Adolescents with CF will be asked to actively express their experiences with their disease and treatment regimen through creation and sharing of illness and self-management video portraits. Each video assignment will ask teens to show and tell how they handle some key aspect of self-management (e.g., taking enzymes at school), explore how they handle key self-management skills (such as setting goals and milestones) and develop a short narrative reflection on the impact of that self-management issue on their quality of life, goals for the future, and relationships with their parents. Adolescents will share these portraits and reflect on their significance together through monthly online virtual meetings. Special online sessions will also be developed for parents. Intervention Mapping, a systematic planning process for intervention development that specifies procedures for integrating theoretical constructs and empirical evidence, has guided preliminary development of the intervention. For the formative evaluation of the intervention, 36 adolescents will be randomly assigned to either the Peer Group Intervention or a Usual Care control group. Measures of physiological indices, quality of life, self-management behaviors, self-efficacy, and family cohesion will be collected longitudinally, starting at baseline and extending for 8 months beyond the 6-month intervention period. Analysis of these measures will provide a signal of efficacy and reliable estimates of parameters needed for planning a randomized controlled trial in the future, should the Peer Group Intervention prove promising. Narrative analysis of the video portraits as well as qualitative analysis (of the online sessions and exit interviews with the intervention participants) will shed light on the soundness of the theoretical premise and produce new knowledge about the burdens, barriers and opportunities for successful self-management of this pediatric chronic illness. This study will provide evidence for a potential break-through in existing theories of self-management. It will also provide a new practical approach to self-management for young people with CF, who must now manage their illness in an era of infection control, which has eliminated nearly all forms of face-to-face interaction.